Stairs let interior designers show off their best combination of form and function. The flagship stores, public works, and designer condos of New York make for the perfect opportunities to test the boundaries of practicality and beauty in design. Here are seven of the most beautiful and interesting staircase designs to be found in New York City.

Three of the staircases on the list come from flagship store locations in New York City, part of a sort of arms race of beautiful retail stairs. Steve Jobs theorized that an irresistible staircase would keep customers in the store longer by strongly encouraging them to visit the second and third floors. His own design is the first staircase on our list. The stairs in the Fifth Avenue Apple Store are a famous example of Steve Jobs’ attention to detail: He conceived and designed the stairs, and his name is on their 2002 design patent.

The New York University Philosophy building sports this beautifully irregular staircase designed by Steven Holl Architects. In addition to its unconventional shape, the monochromatic stairs have another surprise: Prismatic film on the windows casts a rainbow of light into the stairwell at certain times of day. The effect is so striking that much of the building now uses this same “porous” design of white material dotted with holes.

These incredible (and incredibly difficult to photograph) stairs were designed by Massimiliano Fuksas for the Armani flagship store on Fifth Avenue. Where the stairs actually lead to or come from will certainly make you think of an M.C. Escher lithograph upon first look.

Thomas Heatherwick and Heatherwick Studio designed these incredible “wavy” stairs in La Maison Unique, a Longchamp flagship store in SoHo. The stairs are rubber-coated steel based on the concept of a zipper, fitting for Longchamp’s bags and leather goods.

Images courtesy of Franklin D. Roosevelt Four Freedoms Park, LLC

Four Freedoms Park ↑

These steps may be built from humble concrete, but their sheer scale and the vantage they offer is inimitable. Four Freedoms Park on Roosevelt Island was designed by architect Louis Kahn (interestingly, constructed four decades after the architect’s death) as a posthumous memorial to Franklin D. Roosevelt. The Guardian’s Oliver Wainwright in 2014 described this as Kahn’s best project, and even more aptly as an “ancient temple precinct” in NYC.

Images via nC2 Architecture

M Lofts Stairs by nC2 Architecture ↑

It may look like these stairs in a Brooklyn apartment can’t be climbed, but the designers at nC2 Architecture say it is perfectly safe and functional. The steps also provide for a bit of storage and, if you’re wondering, lead to a lofted bedroom.

This penthouse at the Delos lingered on the market for two years before it was finally scooped up by a buyer for $26 million last fall (nearly half it’s original asking price). While the apartment, like the building, is known for hosting eco-friendly features such as Vitamin C-infused showers and circadian rhythm lighting, it is the incredible staircase that really stands out in our eyes. The piece is a three-story custom crafted metal design that has been dramatically set against a single-pane, two-story glass window and atrium.